“If there is any effect at all, it is quite small,” says Roy Baumeister of Florida State University. He was the lead author of a 2003 paper that scrutinised dozens of self-esteem studies.

He found that although high self-esteem frequently had a positive correlation with success, the direction of causation was often unclear. For example, are high marks awarded to people with high self-esteem or does getting high marks engender high self-esteem?

And a third variable can influence both self-esteem and the positive outcome.

“Coming from a good family might lead to both high self-esteem and personal success,” says Baumeister.

“Self-control is much more powerful and well-supported as a cause of personal success. Despite my years invested in research on self-esteem, I reluctantly advise people to forget about it.”